Virtual colonoscopy (VC) refers to a method of diagnosis based on computer simulation of standard, minimally invasive endoscopic procedures using patient specific three-dimensional (3D) anatomic data sets. Examples of current endoscopic procedures include bronchoscopy, sinusoscopy, upper gastro-intestinal endoscopy, colonoscopy, cystoscopy, cardioscopy, and urethroscopy. VC visualization of non-invasively obtained patient specific anatomic structures avoids risks, such as perforation, infection, hemorrhage, and so forth, associated with real endoscopy, and provides the endoscopist with important information prior to performing an actual endoscopic examination. Such information and understanding can minimize procedural difficulties, decrease patient morbidity, enhance training and foster a better understanding of therapeutic results.
In virtual endoscopy, 3D images are created from two-dimensional (2D) computerized tomography (CT) or magnetic resonance (MR) data, for example, by volume rendering. Present-day CT and MRI scanners typically produce a set of cross-sectional images which, in combination, produce a set of volume data. These 3D images are created to simulate images coming from an actual endoscope, such as a fiber optic endoscope.
In the field of virtual endoscopy and, more particularly, in the field of virtual colonoscopy, it is desirable to provide for synchronization of different endoscopic views, such as views acquired in prone and supine positions of a patient. This facilitates the identification of features in the different views and facilitates, for example, the parallel study of prone and supine acquisitions in colon cancer screening.
Existing methods for synchronizing such views typically assume that a colon centerline is formed of a single connected component. See, for example, B. Acar, S. Napel, D. S. Paik, P. Li, J. Yee, C. F. Beaulieu, R. B. Jeffrey, Registration of supine and prone ct colonography data: Method and evaluation, Radiological Society of North America 87th Scientific Sessions, 2001; B. Acar, S. Napel, D. S. Paik, P. Li, J. Yee, R. B. Jeffrey, C. F. Beaulieu, Medial axis registration of supine and prone CT colonography data, Proceedings of 23rd Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC 2001), Istanbul, Turkey, 25-28 Oct. 2001; and D. Nain, S. Haker, W. E. L. Grimson, E. Cosman Jr, W. Wells, H. Ji, R. Kikinis, C.-F. Westin, Intra-Patient Prone to Supine Colon Registration for Synchronized Virtual Colonoscopy, In Proceedings of MICCAI 2002, Tokyo, Japan, September 2002.